Marble incorporating iron core

ABSTRACT

[Object] It is an object of the present invention to provide a marble having higher impact resistance than that of a marble of glass conventionally known, capable of being played by using a magnet and easily enhancing decorative properties.  
     [Means for Settlement] A marble incorporating an iron core of a round ball is composed by covering the entire outer surface of an iron core with a jacket made of a synthetic resin.

The present invention relates to a marble for decoration or use in various ball games. In one of the game, children compete for the marble by rolling and hitting one marble to another to flip it due to its impact. Such marble has a diameter of 1 to 2 cm. In the present application, “marble” means a sphere for games regardless of the material.

BACKGROUND OF THE INVENTION

Though the marble has been known as a toy of a sphere of glass for many years, recently, a sphere made of a synthetic resin, an iron ball and a marble of non-glass have been also available commercially. In the marble of non-glass, one half of the sphere is formed of metal and the other half is formed of a synthetic resin. The weight of one half being heavier than that of the other half, and thereby the sphere is irregularly rolled. Moreover, Morita (Japanese Patent Laid-Open No. 1999-348994) teaches a soda water ball a short pillar-like hard core material penetrating through its elastic ball body such that the both end faces of the core are exposed to the outer surface of the ball body.

SUMMARY OF THE INVENTION

The size and weight or the like of the marble of glass used for many years is suitable for the toy. However since the marble is formed of glass, a problem is left in impact resistance.

Though an iron ball and a plastic ball have high impact resistance, the iron ball is too heavy and a plastic ball is too light. Thereby, the iron ball and the plastic ball cause sense of incongruity remains.

It is a primary object of the present invention to provide a marble which enhances impact resistance by covering the entire outer surface of a iron core with a jacket made of a synthetic resin.

It is a secondary object of the present invention to provide a marble which has a suitable weight, preferably the same weight as that of a glass ball having the same diameter.

A third object of the invention is to provide a marble which can be played by using a magnet since the iron core is contained.

And a fourth object of the invention is to provide a marble which enables printing on the outer surface by using a synthetic resin for the jacket, and excels in decorative properties.

As a first means for achieving the above-mentioned object, a marble incorporates an iron core also has a jacket made of the synthetic resin for covering an entire outer surface of the iron core, wherein the jacket is shaped into a second round ball.

According to this means, the marble having a moderate weight can be composed since the iron core is heavy and the jacket is light. Also, since the marble has the iron core, the marble can be played by using the magnet. Since the outer surface is covered with the jacket made of the synthetic resin, the impact resistance of the marble can be enhanced. Since the outer surface of the marble is also easily printed and colored, the decorative properties of the outer surface can be made beautiful.

As a second means, the iron core is shaped into a first round ball.

According to this means, the center of gravity is easily set to the center of the ball, and thereby the thickness of the jacket can be easily equalized in each part of the ball.

As a third means, the above second round ball has the same weight as that of a glass sphere having the same diameter as that of the second round ball.

According to this means, since the marble of the present invention has the same size and weight as those of the conventional marble of glass, a sense of incompatibility is not generated at the time of playing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a marble according to the present invention.

FIG. 2 is a sectional view showing the state of the midway of the manufacture of the marble shown in FIG. 1.

FIG. 3 is a sectional view showing the state where the marble shown in FIG. 1 is manufactured in a metal mold.

BEST MODE OF THE INVENTION

The drawings will be described below. Numeral 1 designates a sphere used as a marble, and an iron core 2 is buried at the center of the sphere. The core is covered with a jacket 3 made of a synthetic resin.

In the embodiment shown in FIG. 1, the diameter of the core 2 is set to about 10 mm, and the core 2 is composed by a first iron round ball 2 a of about 4 gram. The entire outer surface of the first round ball is covered with an ABS resin, and thereby a second round ball 1 a having a diameter of about 16.7 mm is composed. The weight of the second round ball 1 a is about 6 gram. The weight of the second round ball is almost equal to that of the marble of glass having the same size as that of the second round ball. The size and weight of the marble are not particularly limited, and the size and weight of the above embodiment may be suitably changed. However, in that case, the weight of the second round ball 1 a is particularly preferably almost equal to that of the marble of glass having the same diameter of the second round ball. Thereby, the above marble incorporating the iron core can be used with the same feeling as the marble of glass which has been fitted for years, and the thickness of the jacket to the first round ball 2 a can be also moderately kept.

The first round ball 2 a is located at the center of the second round ball 1 a, and the thickness of the jacket 3 is entirely equalized. The core may be covered with the jacket 3 by using known methods.

In the example shown, as shown in FIG. 2 and FIG. 3, the core may be covered with the jacket by insert molding. That is, as shown in FIG. 2, one half of the first round ball 2 is fitted to a recess 13 of a first metal mold 12, and the other half is exposed. The exposed other half of the first round ball is projected into a first cavity 15 of a second metal mold 14. After the metal molds are closed, the first metal mold 12, the first round ball 2 a and the second metal mold 14 form the first cavity 15 into which a molten resin material is ejected from a first runner 16 formed on the second metal mold, such that the jacket 3 is adhered on the outer surface of the other half of the first round ball 2 a. Then, both the metal molds are opened, and the first metal mold 12 is removed. One half of the first round ball 2 a is projected into a second cavity 17 of a third metal mold 18 having a second cavity 17 instead of the first metal mold, and the second metal mold 14 and the third metal mold 18 are closed. The molten resin material is ejected into the second cavity 17 from a second runner 19 of the third metal mold from the state, and the outer surface of the first round ball 2 a is covered with the jacket 3. Both the metal molds are opened to take out the second round ball 1 a. 

1. A marble incorporating an iron core and also having a jacket made of the synthetic resin for covering an entire outer surface of the iron core, wherein the jacket is shaped into a second round ball.
 2. A marble incorporating an iron according to claim 1, wherein the iron core is shaped into a first round ball.
 3. A marble incorporating an iron according to claim 1, wherein the above second round ball has the same weight as that of a glass sphere having the same diameter as that the second round ball.
 4. A marble incorporating an iron according to claim 2, wherein the above second round ball has the same weight as that of a glass sphere having the same diameter as that the second round ball. 